The present invention relates to information storage devices, memory access control methods, and computer programs. More particularly, the present invention relates to an information storage device for performing unlocking of a memory in response to a command input from an information processing apparatus, and, when the information storage device is turned off and then on, recreating lock status data prior to the memory being unlocked and performing memory access control based on the recreated lock status, to a memory access control method, and to a computer program.
Various information processing apparatuses, such as PCs (Personal Computers), PDAs (Personal Digital Assistants), digital cameras, data readers/writers, and game machines, read and write data using various storage media, such as hard disks, DVDs, CDs, and memory cards.
Nowadays, small card-type memory devices, each including a memory such as a flash memory or the like and a controller such as a CPU or the like, are widely used as storage means for storing various types of software data (content), such as music data, image data, and programs.
Reading of data stored on a memory card or the like or writing of data to such a memory card is done by placing the card in a unit with a memory card interface and transferring data via the interface. Data reading and writing using a memory device may be done by anyone without permission. Alternatively, a so-called access control scheme is implemented by, for example, setting a password or performing encryption so that only a specific user or a specific unit is permitted to access the memory, whereas a third-party user who does not have permission is denied access to the memory.
For example, a password known only to a user who has access permission is generated. This password is transferred from a content-using unit serving as an information reader to a content storage unit, such as a memory card. A controller (CPU or the like) of the memory card verifies the password and, only if the verification succeeds, content is output from the content storage unit, such as the memory card, to the content-using unit serving as the information reader. Alternatively, mutual authentication is performed between the content-using unit serving as the information reader and the content storage unit, such as the memory card. Only if the mutual authentication succeeds, content is output from the content storage unit, such as the memory card, to the content-using unit serving as the information reader.